


You Are What You Eat

by timkons



Category: Haikyuu!!
Genre: Alternate Universe, Consensual Kink, Dark Comedy, Established Relationship, Fake Science, M/M, Macro/Micro, Masturbation, Mouth Kink, Oral Sex, Road Trips, Size Difference, Size Kink, Summer Vacation, Voreish
Language: English
Status: Completed
Published: 2017-06-14
Updated: 2017-06-14
Packaged: 2018-11-13 23:19:14
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,211
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11195556
Author URL: https://archiveofourown.org/users/timkons/pseuds/timkons
Summary: Dr. Tetsurou Kuroo, (ex-)MD, has an annual ritual to take his boyfriend on a summer vacation. All Kuroo wants is to get to the damn beach, sip some fruity drinks in the sand, and dip his toes in the ocean with said boyfriend. Unfortunately, actually getting to the beach is proving to be a problem. A seven-hour drive with Bokuto in the car is bad enough, but a seven-hour drive with Bokuto in a Smart Car is just killer. Luckily, Kuroo has a solution for this year's summer road trip.





	You Are What You Eat

**Author's Note:**

> feel free to hmu on [tumblr](https://90stimkon.tumblr.com/) or [twitter](https://twitter.com/cloneboys), or [consider commissioning me](https://90stimkon.tumblr.com/post/162750545663/commission-me)!

Bokuto takes a final look at the vial of purple liquid he’s holding, wincing as the bubbles pop from carbonation. He continues to flip the vial over and over, which doesn’t help with the bubbles brewing within it, “Are you sure about this?”

Kuroo takes a seat, knowing that he’ll need it. He breathes in deeply, clasps his palms together, and prepares to explain it to Bokuto for the fifteenth -- and hopefully final -- time. “We’re doing this so it will be cheaper. If we cut down on things like food and the car rental, then we can use that money for _awesome_ things, like sipping fruity drinks on the beach.”

“But I could drive! And then it’ll cut our traveling time,” Bokuto protests, speaking more with his hands than his words.

Kuroo uses his special “No, Koutarou” look and “No, Koutarou” voice, patents pending. “I love you, babe, but I got two words for you: last. Summer.”

His boyfriend’s cheeks flush red immediately and his eyes glance to a spot on their wall where the wallpaper is peeling. “I didn’t _mean_ to fall asleep at the wheel.”

“Thanks for reminding me about that,” Kuroo says, haunted, “but I meant how you got two tickets _and_ nearly drove off a bridge!”

“You’re always holding that against me,” Bokuto mutters bitterly.

Kuroo rolls his eyes, knowing very well that if he engages they’ll both derail the conversation and end up laughing, and he can’t have that happening now, not when they’re all packed and ready to go except for this one big -- soon to be little -- thing. “Drink the damn serum so we can go, Kou.”

Just when Bokuto uncorks the vial and Kuroo’s ready to dash out of their apartment with their packed backs, Bokuto hesitates. “It’s safe?”

“One hundred percent safe. Made it myself.” Kuroo may have lost his license for malpractice and he may be blacklisted from at least three choice pharmaceutical companies, but he’s always been good with chemicals. When his boyfriend mentioned a cross-country trip to the beach for this year’s summer vacation, Kuroo had been ecstatic, but their joint funds had not. He’d come up with a solution involving some chemicals he may or may not be banned from legally having in his possession, but it’s for the greater good. “It’ll wear off in twelve hours, plenty of time for us to get to the beach and sleep it off. You’ll be your usual, handsome self by the time you wake up.”

Kuroo can see it in Bokuto’s eyes when he continues to stare suspiciously at the purple liquid and when he wrinkles his nose after sniffing it; Bokuto’s going to say no. Kuroo smoothly glides out of his seat and takes Bokuto’s neck into his hand. He rubs his boyfriend just beneath the ear, right in that spot that makes Bokuto’s eyes close and his chest rumble with a purr. Leaning his forehead against Bokuto, he reminds, “have I ever done you wrong with one of my concoctions?”

Bokuto bites his bottom lip to stop himself from smiling. “ _Well_ , there was that one time you gave me a boner that lasted a whole day and we nearly had to go to the hospital.”

“But wasn’t it _fun?_ ” Kuroo closes the space between them and kisses Bokuto to loosen where he’s chewing his lip, and Bokuto kisses back.

“Hell yeah,” Bokuto admits softly. His eyelashes flicker from the ground to the wall and then directly to Kuroo. “I don’t want tits again. It was fun the first few times but I like my chest how it is now.”

That time Kuroo does laugh, but he pulls away, letting his hand drag onto Bokuto’s cheek and pet his cheekbone. “No tits, I promise.”

Bokuto takes a deep breath and kisses Kuroo on the cheek before announcing, “bottoms up.”

-

Kuroo’s made some pretty whacky serums, everything from growing tails to making skin turn into a golden shimmer, and just like always with the first time Bokuto tries one of them, Bokuto insists on waiting for the effects to take over by himself, just in case he’s embarrassed, uncomfortable, or anything goes wrong. Kuroo’s insisted that this is actually the opposite of what they should be doing, since Kuroo should be there in case anything goes wrong, but Bokuto’s always been a good sport, even with the side effects, and insists on having time to get used to it.

Usually Kuroo’s restless the entire twenty minutes it takes for his serums to work, mostly because when Kuroo and Bokuto bust out one of Kuroo’s masterpieces it’s for less than professional reasons, but for once Bokuto’s moodiness works out with their plans. Kuroo loads their two duffle bags into the tiny trunk of his smart car. Technically, it’s his company’s smart car, but technically he doesn’t work for them anymore.

He loads a couple more things to make the car feel more like home, like a pair of fuzzy dice around the rear-view mirror and a hula girl and a bobble head for the dashboard. It’s simple, but it will half to do.

It takes less than ten minutes to load the car, so Kuroo wastes another twenty minutes grabbing some drinks from the convenience store around the corner and double checking their map. By the time he has the playlist for their trip ready, it’s about That Time, and he knocks on their bedroom door. “All good? Ready to go, Kou?”

“I can’t open the door!” Bokuto’s voice, though higher pitched than Kuroo is used to, says from behind the door.

“I’m coming in,” Kuroo warns before he enters. The first thing he notices is how their bedsheets have been knotted into a makeshift rope connecting it to one of their shabby dressers, but it’s not long before his eyes land on Bokuto, albeit a smaller version of him, standing proudly on top of the dresser. He’s made it to the Barbie doll outfit that Kuroo left out for him, and looks quite appealing in Malibu Ken’s Hawaiian shirt and khaki shorts. The clothes are a little baggy since Bokuto’s smaller than expected, but Kuroo can always adjust the formula next time. “ _Aww_ , you’re so cute it makes me want to stuff you in my pocket.”

“Not your back pocket!” Bokuto squeaks, but he climbs onto Kuroo’s forearm when it’s extended to him. He huffs a little, and Kuroo tries to retrain a shiver of feeling Bokuto’s little fingers and toes press against his skin like a bug. His skin prickles and the hair on his arm rises. “Your huge ass would kill me like this!”

“My _perfect_ ass takes offense to that,” Kuroo says dryly, but he’s more focused on observing Bokuto. Once a scientist, always a scientist, licensed or not. “What happened to the shoes?”

“Have _you_ ever tried walking in plastic? It sucks. I’m just going without,” Bokuto says, still struggling up Kuroo’s arm by grabbing onto his arm hairs and hoisting himself up one-by-one. Hissing from pain, Kuroo practically scoops him up and Bokuto crawls up his sleeve until he’s sitting on Kuroo’s shoulder and clinging to his neck and hair. “Dude, you really gotta clean your ears. It’s wax central right now.”

It takes everything in Kuroo not to start analyzing Bokuto’s body and ask him a million and one questions about the results, but he can do that another time, say, after they’ve made the trip back home. Kuroo lets the comment about his ear slide since he figures he’ll be annoying Bokuto for the next twelve hours with size puns and calling him cute, which Bokuto appreciates but not excessively.

“Babe, I know I’ve said before that size doesn’t matter but it really does,” Kuroo laughs while poking at Bokuto’s face. It’s surreal seeing him this tiny, even if he made the damn medicine.

“Hey, you’re the one who said I had to be tiny!” mini Bokuto belts. He shoves Kuroo’s hands away, some of his strength retained despite his short stature. “Weren’t you the one that wanted to go? We’re wasting time!”

“Holy shit you’re still strong,” Kuroo hisses when Bokuto starts to yank at his hair. Bokuto tugs on his hair, yanking himself up to the top of Kuroo’s head, and though it’s uncomfortable, Kuroo’s glad to see Bokuto seems as energetic as ever. “But seriously, you okay? Nothing feels off?”

“Everything feels fine. Now onward ho, noble steed!” Bokuto announces, fisting two strands of hair and kicking the heels of his feet against Kuroo’s forehead. So much for Kuroo worrying about him; Bokuto’s acting like he’s riding a god damn dragon.

-

“Hello, Kuroo-san. Going on a trip?” their landlady says, sweeping the stretch of floor that separates Kuroo from the garage.

He breathes in sharply, unable to forget Bokuto with the way he squeezes and fights with Kuroo’s hair, but their landlady pays no mind. “Yeah… I’ll be gone for a week with my friend. Going to the beach.”

“That’s wonderful. The beach is lovely this time of year.” She smiles, and Kuroo’s heart is beating rapidly with how well this is going. He has no idea why she’s not asking about the tiny person on his head. After a bit her smile drops and she blinks, looking around Kuroo’s shoulder. “Where is he, by the way?”

“Uh.” He feels his stomach drop. Kuroo feels a tug a small whisper from Bokuto: ‘ _car._ ’ “He’s in the car already.”

“What a shame. I didn’t see him pass by and I wanted to give him a good sendoff too. Well, be careful on your trip,” she says, returning to her sweeping as if Kuroo isn’t trying to sneak his Barbie-sized boyfriend out of the apartment.

Kuroo lets out a deep exhale as walks to his car. It’s not until he’s done fumbling for his keys and opening the door that he remembers what words are. “How the hell did we get past that?”

“I hid in your bedhead, dude,” Bokuto says. Kuroo looks into the rearview and sees Bokuto’s head peek out of the cocoon he’s made, grinning. Kuroo waits until Bokuto’s crawled down and drops down his arm like it’s a slide before shaking his head.

-

“We wouldn’t have fit in here together,” Bokuto admits, fifteen minutes into the trip. They’re still in the city and would be for about twenty minutes more, but already Bokuto’s explored every inch of the car from the perspective of his new form. “It’s kinda cool. Everything looks so big when you’re this small.”

“Liking it already?” Kuroo says, whistling.

“I didn’t say _that_.” Bokuto’s trademark huff is adorable, but as a pen-sized version of himself, Bokuto’s trademark huff is gut-wrenchingly _adorable_. He sits in the middle of the blanket nest Kuroo prepared on the passenger seat for him, legs and arms both crossed. “But it saves us money. We don’t have to rent a car if I’m small.”

“Sure,” Kuroo coos, patting Bokuto on the head like a little pet.

-

Kuroo allows Bokuto to choose the music since he’s the one who’s been turned into the size of a ruler. Bokuto’s first choice is his favorite power ballad, and although he belts out the song as he always does, Kuroo’s ears ring from the new falsetto voice.

-

In the middle of an air-guitar solo that Bokuto is absolutely _jamming_ to, he jumps off the fuzzy dice he was riding like a bull and start headbanging with the Batman bobblehead bouncing on the dashboard until the end of the song. Trumpets start blaring from the radio with the next song starting up, and Bokuto lets out a high-pitched, “oh _shit!_ ” once he recognizes the song. Kuroo glances over to see Bokuto shaking his hips with the hula girl and trying to belly dance. “My hips don’t lie, Tetsu!”

Kuroo officially decides Bokuto needs to be tiny for all future road trips.

-

“Did you pack me any different clothes?” Bokuto asks, now laying on his back in the nest again. Tuckered out from singing and dancing his heart out, Bokuto’s starting to curl up like he wants to take a nap. Another pro of mini Bokuto on a road trip? His energy can be managed. At full size, he’d be driving Kuroo up the wall with his whines of, “I’m _bored_ ,” and, “there’s nothing to do,” and, “can I give you a handjob while you drive?” Actually, that last one was always good, but it was equally distracting.

“Yeah, I packed everything you left out on the bed. And your swim trunks, which you forgot.”

“No, I mean for now. The clothes are attached with velcro and it’s scratchy,” Bokuto complains. Kuroo hears the fastener rip apart and Bokuto kicks off his shorts. It’s kind of a ridiculous scene and he can’t help but laugh, especially since Ken dolls don’t come with underwear, so Bokuto’s little penis and balls peek out under the shirt.

“Yeah, I thought it might be a problem. I had to buy two extra Barbies just for it, but you have your choice of beachwear couture or medical chic,” Kuroo says with a fancy wave of his hand.

Bokuto groans, rolling over dejectedly. “You got me swim trunks and scrubs? I’m gonna look so uncool.”

“Hopefully nobody will be seeing you,” Kuroo reminds. It was sooner than expected for Bokuto to get tired of his clothes, but it was only a seven-hour drive to a _very_ satisfied off-the-books client’s personal beach, where they would be staying for the week. After a few taps of his fingers against the driver’s wheel, Kuroo decides it wouldn’t hurt to speed their schedule up a bit. “Check the inside pocket of my backpack.”

Bokuto perks up and jumps to the ledge of the seat and drops down. Kuroo’s only mad that Bokuto’s ass looks just as perfect 75% smaller. Bokuto’s excited voice is, however, 75% louder and higher. “Oooh! These aren’t too bad.”

It’s a flat stretch in the country, so Kuroo takes his eyes away from the road just long enough to see Bokuto toss the pieces of clothing on the seat and crawl back up. He watches Bokuto look at each piece one-by-one, even though it isn’t a lot. “I know how much you like to play doctor.”

“Cool,” Bokuto says, whistling, and holds up the white jacket. He places it besides the pair of long pants and button-up -- or, rather, velcro-up -- shirt, and smooths it out. “We gotta scratch the name off and write Bokuto-sensei on it though.”

“Sure, whatever you want, _Sensei,_ ” Kuroo says. He feels his fingers curl around the steering wheel and bites his lip as Bokuto inspects the next outfit. “Figured that one was more in line with the season.”

“I totally rock crop tops,” Bokuto says, wiggling into the piece. It’s longer than how the crop top fit the doll, resting just above Bokuto’s bellybutton, but Bokuto’s chest is much thicker and he barely squeezes into the shirt. The booty shorts also look too tight, obviously made for different proportions than a human body. “These feel better too. A little tight, though.”

“All your clothes are too tight,” Kuroo snorts. Yes, it’s irresponsible to take his hands off the wheel while driving, but yes, he does it anyway to snap a pic of Bokuto modeling the new outfit.

-

“Having fun?” Kuroo asks, grinning as Bokuto takes selfies out of the corner of his eye. Bokuto’s barely bigger than his iPhone but he tilts it along the back of the seat so that it’s just right for his size, propped up like a full-length mirror. By now Bokuto’s kicked and rearranged the nest to suit his needs, and the last position Kuroo saw was of Bokuto kneeling away from the phone, chin hooked over his shoulder and boldly smoldering at the camera, stretching the booty shorts so that his balls hang out of a leg. “You better send me some of those.”

“If you buy me junk food for lunch, maybe I will.”

-

Ever the giver, Kuroo pulls off the main road into the nearest exit that has a McDonald’s. Bokuto demands a McFlurry, a 10-piece chicken nuggets, two of the fancy seasonal burgers, and an extra large fry, but Kuroo buys him a McNuggets Happy Meal. 

“I wanted a McFlurry,” Bokuto reminds pointedly, using his whole body to dip a chicken nugget into the dipping sauce. It’s easier while they’re idling in the parking lot instead of on the road, but Bokuto’s still having some difficulty. Kuroo snaps a quick pic of Bokuto struggling to move his food around as he scrolls through the selfies Bokuto just texted him.

“I’ll go through the drive-through again and buy you a McFlurry if you eat your whole Happy Meal,” he promises in a sing-song voice.

Bokuto looks up with a wide smile and strikes a victory pose.

“You never learn,” Kuroo sighs a bit happily, watching Bokuto rip into his nugget in determination.

-

“I’m so full I can’t move,” Bokuto moans after eating one-and-a-half nuggets. The first had gone down easily enough, but Bokuto could barely keep nibbling the second, and by a fourth in, Bokuto had given up. He flops on his back and moans some more while Kuroo steals one of his fries, licking off the grease from the burger he’d already finished. “Hey! That’s my fry!”

“You’re not gonna eat it now, are you?” Kuroo waves the fry tauntingly above Bokuto, making his point clear. “Told you we’d save on food.”

Bokuto’s only response is to moan some more. “I feel so _full_. If I get back to my size and I’m fat because of one chicken nugget…”

“That won’t happen,” Kuroo assures, stealing another fry, and just as matter-of-factly and quickly, promises, “and even if you get fat off one chicken nugget, I’ll still love you all the same.”

Bokuto moans a third time, but this time it sounds pleased. “I love you _so_ much, Tetsu. You’re the best.”

“Don’t I know it,” Kuroo says with a wink. He makes the error of looking at Bokuto, whose eyes are sharp and fixed on Kuroo.

In a display that’s far too flashy to be accidental, Bokuto dips his arm into his barbecue sauce and holds it out expectantly to Kuroo. “Suck my arm off.”

It’s not the weirdest request Kuroo’s heard, what with clients asking for all kinds of outrageous things and Bokuto being completely shameless with his experiments, but it’s still pretty damn weird. “What.”

“C’mon, suck my arm!” Bokuto says again, now waving his arm so much that little bits of barbecue sauce drip onto the upholstery. He wiggles his fingers seductively, licking his lips. “It’s all sticky and I’m too small for a sink or wet napkins. You’ll drown me!”

“And me swallowing you is _so_ much better,” Kuroo says dryly, but he’s considering it. Worst case scenario, he sucks too hard and swallows one of Bokuto’s fingers, but then again, he has a buddy that works with black market stem cells.

“Suck it off or I dipped my arm in barbecue for nothing and it’ll feel funny for the rest of the trip!” Bokuto prompts, now red in the face from the realization of what a bad idea this is.

“Okay, okay! I’ll…suck your arm,” Kuroo relents, unable to take the sight of Bokuto crying. He’s not crying -- yet -- but he’s sniffling as if he might start any second now. With a sigh Kuroo grabs a napkin and covers bokuto with it, lifting Bokuto toward his mouth carefully. Cupping Bokuto so that they’re both comfortable, he takes a deep breath. “Just so you know, this is a _terrible_ idea.”

“It’s an _awesome_ idea,” Bokuto corrects, smearing the sauce off his hand on Kuroo’s bottom lip, and when Bokuto says it like that, even Kuroo gets a little bit excited to try it out. Kuroo licks at Bokuto’s small arm, allowing his boyfriend to get used to the texture of his tongue before making a small, ‘o,’ with his lips and letting Bokuto slide his arm inside. Immediately Bokuto wiggles his arm, and of course it’s weird but not altogether unpleasant, especially when Bokuto sighs blissfully. “Your mouth’s so warm and _wet_. It feels great.”

Kuroo hums, which unexpectedly tugs a gasp out of Bokuto and his entire body twitches in Kuroo’s hand. He tries it again, experimentally, but Bokuto only shudders. “That… That’s really good.”

Encouraged, Kuroo begins lightly sucking on his boyfriend’s arm and even dares to slide his tongue against Bokuto’s flexing bicep. He feels the light scratch of Bokuto’s small nails against his tastebuds and accidentally swallows.

“Too much!” Bokuto hisses, voice somewhat pained, and Kuroo spits him out immediately.

“Are you hurt? Do you have all your fingers?” Kuroo rattles off worriedly while poking Bokuto to check his body. He was the only doctor in the car, after all, licensed or otherwise, and his heart stops racing when Bokuto doesn’t show any outward symptoms of harm. 

“I’m fine! I’m fine!” Bokuto insists, slumping into a seated position and flicking Kuroo’s saliva off with a full-arm shake. “Don’t mind. My shoulder felt like it was gonna get dislocated if you sucked any harder is all.”

“I told you it was a bad idea,” Kuroo grumbles.

“Stop saying all my ideas are bad ideas. I liked it.” Bokuto stubbornly presses to his tip toes and leans up to place a small kiss on Kuroo’s bottom lip. “I can’t tell what I like better: your mouth doing _that_ or your mouth giving me head. And see? My arm’s all clean!”

-

Kuroo gets back on the road after their finishing Bokuto’s fries and wiping Bokuto down with a wet wipe despite his protests. Bokuto returned to his nest, skulking, and said, “it’s not like it’s the first time I’ve been completely covered in your fluids.”

Bokuto had a point, but Kuroo still refused to budge the car until Bokuto let Kuroo clean him. And so, Bokuto’s wrapped up in the nest again, refusing to come out. Kuroo knows better than to try and pull Bokuto out of one of his slumps -- literally, in the case, since he could pick Bokuto up and sit him on his lap -- but it would be too demanding. He knows his boyfriend needs time to work through his emotions, especially the bad ones, and he figures that’s what all the soft grumbling and the occasional growl or buzz coming from the nest of blankets is for.

“Tetsu, are you going to get distracted if I masturbate?”

“I’m just surprised it took you this long to ask,” Kuroo confesses, though admittedly he expected Bokuto’s mood to be in one of his unforgiving swings, given the situation. “How are you turned on anyway?”

Bokuto’s head peaks out of the nest and he sticks his tongue out at Kuroo. “I’m always turned on when you suck me off.”

“That’s because I’m sucking your _dick_ , not your arm,” Kuroo points out.

“And when you suck on my fingers. Arms aren’t so different from fingers.” Bokuto’s form wiggles from beneath the blanket and his face gets red. “I’m dying, dude. I’m so hard right now and all I can think is of is your tongue between my thighs.”

Opening his mouth to retort, Kuroo finds all his words are gone. He licks his lips, actually trying to imagine what that must feel like for Bokuto now, knowing he’s so sensitive, and he restrains a moan. “We can try that.”

“Really?” Bokuto asks hopefully, now smiling. “You don’t think it’s weird?”

“Babe, I made you the size of a Barbie doll, and that’s just the tip of the iceberg of crazy stuff we’ve done together,” Kuroo reminds. Personally, the auto-lubrication serum was his personal favorite, especially when they both drank it and ate each other out for hours on end. “Do you really think I’d judge you for that? What’s a little vorarephilia between boyfriends?”

“Yeah?” Bokuto asks again, though this time Kuroo knows it’s just to boost his ego. “So you don’t mind if I--” And Bokuto was cheeky about it, as always, standing up and letting the blanket flutter to his ankles, to reveal himself in the buff. “--lay back here and think about your tongue out loud?”

“Go ahead,” Kuroo said with a smirk, now unable to keep his eyes on the road for more than five seconds at a time.

Removing the blanket dramatically, Kuroo notices for the first time that the wiggling might have been Bokuto moving things into place just for this. He’s rather impressed with how Bokuto managed to pull their bottle of lotion out of Kuroo’s backpack without him noticing, and Bokuto’s phone is laying flat against the seat.

“Do you have a condom on you?” Bokuto asks casually while opening the cap of the lotion and dragging it into place. Bokuto kneels on his phone’s surface, now beckoning for the condom.

“Yeah, in my wallet, one sec,” Kuroo says, shimmying in his seat to fish out his wallet.

“You shouldn’t keep them in there,” Bokuto reminds, lounging against his phone as comfortably as he lounges on their couch at home. “Friction makes them dry up. Dry condoms are bad condoms.”

“Remind me who the doctor is?” Kuroo finds the condom and drops it into his lap while slipping his wallet into his back pocket again. He flaps the condom above Bokuto tauntingly. “Want me to open it or can you manage?”

“Open it for me,” Bokuto says with some embarrassment, or maybe he’s just impatient. Kuroo rips it open with his teeth and offers the packet to his tiny boyfriend, who makes a sound of approval. Bokuto scrambles up to retrieve it and begins to move it in place. “Thanks, babe.”

“No problem,” Kuroo says, assessing Bokuto’s set up. The condom makes sense as a barrier and Bokuto’s already pushing out some lotion onto one palm by sitting on the bottle of lotion, but… “What’s the phone for?”

“I have another really good idea,” Bokuto says vaguely, winking. The little bit of lotion is enough to smear between his thighs and ass, and with his dry hand, Bokuto wakes up his phone, manages to unlock it, and hits his timers. He has a number of them set moments after each other, set to silent with only vibration, and Bokuto begins to ride the corner of his phone. “Not as good as your, _hnngh_ , mouth-- but--”

“Holy shit,” Kuroo breathes. Apparently Bokuto being smaller and with the way he jerks his tiny dick and lets his balls hang over the corner, allowing the vibrations to stimulate them as well as his taint, means the vibrations are stronger.

“So strong,” Bokuto breathes out, and Kuroo sees how his legs start to squirm and his hips wiggle against the vibrations and Bokuto arches his back, slipping against the condom, hand wildly slipping up and down his dick. “Want your tongue making me feel this -- haahn -- _good!_ I’m—mmm _mm_ \--”

Bokuto coming fast usually means a minute or two, not _instantly_. Kuroo nearly crashes the car, but the sight of Bokuto tilting his head back when he comes is a death worth dying. Kuroo swallows thickly. “Is it weird if this is turning me on?”

-

It’s more humid in the car after Bokuto gets himself off again, and it isn’t humid because of Bokuto. He blissfully takes a nap after his orgasms while Kuroo brews in sexual frustration, and he lets out the most innocent sounding yawn when he wakes up, stretching like a fairy out of a Disney movie. Kuroo considers that maybe driving while horny is worse than two extra hours on their driving time and Bokuto’s bulky figure shoving Kuroo against the windows with his elbows.

-

Newly energized, Bokuto starts to swing off the fuzzy dice again, singing along with the song. It’s not so bad for short periods of time, but it’s blocking the view of the road and Kuroo tells him to get down. Bokuto merely kicks his legs with a defiant, “make me!”

“Seriously, Kou, I need to see the road,” Kuroo insists, pinching Bokuto by his crop top and doing his best not to hurt him. Bokuto, playful as ever, grabs one of his fingers and bites. _Hard_. “Ouch! What the fuck? Your teeth are so sharp for being so small!”

“Come on, it’s not _really_ distracting you. Let me swing.” Bokuto starts swinging limply in Kuroo’s grasp, trying to aim himself toward the fuzzy dice.

“Oh, you want to play like that? Fine then.” Calmly, Kuroo dangles Bokuto toward his face and opens his mouth, exaggerating his, “ _ahhhhhn_.”

“Don’t eat me! I’ll be good! No more biting!” Bokuto immediately screams, pressing his entire body against Kuroo’s hand, arms wrapped around a finger and legs wrapped around Kuroo’s wrist for dear life.

“I wouldn’t really do it!” Kuroo huffs, perhaps insulted that his boyfriend doesn’t trust him, as he places Bokuto down in the passenger seat. “Besides, you’d taste like ass.”

“You are what you eat!” Bokuto chirps back with a smirk.

-

“Do you think if we pulled over and bought gas station coffee that I could fit in the cup and make it into a coffee hot tub? I’ve always wondered what that would be like.”

“I’m not pulling over for you to buy coffee and steam in it,” Kuroo says strictly, “but I’ll brew you a large cup when we get to the place.”

-

Every time Kuroo notes the time, he feels a swell in his chest. Non-stop driving isn’t one of his hobbies, and they’ve cut nearly an hour off the driving time without Bokuto’s expected tantrums or side-trips, which he attributes to his grand idea of making Bokuto small.

Sure, there’s been some downsides. A spider crawled in through a vent and Bokuto wouldn’t stop screaming for fifteen minutes after Kuroo killed it, and Kuroo had to hold Bokuto like a little doll as he sobbed and clung to his chest. And there was how Bokuto had solemnly said, “I’m gonna ride it,” when an fly flew in through a cracked window, but Kuroo somehow managed to shoo it out _and_ convince Bokuto that contrary to his belief, he is, in fact, not cut out to be Ant-man.

And then there's now, where five minutes ago they hit a rainy patch that made Bokuto shiver so hard the entire nest shakes with him. At the sound of thunder clapping, Bokuto ducks his head into the covers and wails, “We’re gonna die!”

“We’re not going to die,” Kuroo says, though he turns on the windshield wipers for the light drizzle. “It’s barely raining.”

“It’s so loud!” Bokuto insists from within his nest.

Kuroo sighs and knows what he must do, even though he’ll have to be more careful driving and it might slow them down a bit. He digs into the nest and pries Bokuto, who clings onto his palm like a starfish, out gently. “Come and sit on my shoulder. You’ll feel better.”

Bokuto sobs and shakes against his neck, pressing his face behind Kuroo’s ear. At one point Kuroo thinks he hears -- and feels -- Bokuto blowing his nose into his hair, but that’s something he’ll deal with later.

“Give me your hand,” he prompts, and Bokuto tearfully offers his tiny hand. With a fingertip, Kuroo tilts his chin back only until it’s still safe to see the road and guides Bokuto’s hand to his pulse. He breathes steadily for a few moments and is careful to press Bokuto’s hand against his neck but not too hard. He hears, more than feels, Bokuto’s breathing even out and lean against the shell of Kuroo’s ear.

-

The rain patch clears up a few minutes later, but Kuroo doesn’t notice the change in Bokuto’s behavior until he feels small teeth clamping along his earlobe.

“How soon until we’re there, Tetsu?” Bokuto asks, so close that all he has to do is breathe the question.

“O-One hour.” Kuroo swallows, clenching his eyes shut and hating how much his voice wavers. Bokuto’s soft, higher pitched voice sends a chill down his spine, and Bokuto’s tugging his ears in _just_ the way Kuroo likes. He clenches the steering wheel when he feels Bokuto straddle his shoulder with one leg on either side of his shoulder, and his hands caress the inside of Kuroo’s ear, which he didn’t know was so sensitive until now. “ _Koutarou._ ”

“I can’t wait an hour.” And then there’s a long lick from the middle of his ear up to the cartilage. Bokuto plays with the spot where Kuroo had an earring throughout all of medical school but has since closed up.

Kuroo swallows thickly and floors the gas.

-

Kuroo’s map suggests the remaining distance should take an hour. He makes it in thirty-nine minutes. Jumping out of the car immediately, Kuroo wastes no time stuffing Bokuto into his pocket like he promised and not bothering with their duffle bags. He’s really thanking his client, Mr. [Redacted], right about now. He’ll have to give him a freebie of the ass inflation serum for his charity, but for now he can only focus on how Bokuto’s wiggling from his pocket into his zipper.

-

“Want you so bad. Want you right now. Tetsu, Tetsu,” Bokuto’s already babbling off, as Kuroo pulls Bokuto out of his pants and lays him on the pillow. Bokuto’s shed his crop top and booty shorts somewhere along the way and lets his thighs spread open for his mini-sized cock to stand proudly. “Suck my dick, Tetsu.”

“I-- Damn it, Kou,” Kuroo breathes immediately. He shucks off his pants and shirt because he’s not stupid and wants to get laid, but it’s just like Bokuto to undulate on the mattress in want of sex without thinking things through. “We have to be careful.”

“I know, just suck on me a lil’,” Bokuto begs, thrusting his hips into the air. Kuroo knows Bokuto’s trying to entice him, and damn if it isn’t working.

“Hold still,” Kuroo commands, and leans down to lap at the insides of Bokuto’s thighs. Bokuto’s entire body shivers and he presses himself against the length of Kuroo’s tongue, trying to wrap himself around it.

“Lick my nipples,” Bokuto demands, shimmying down the pillow until his tongue is lathering Bokuto’s chest in saliva. He does his best to kiss around each nipple, but he ends up kissing half of Bokuto’s chest every time, though Bokuto doesn’t seem to mind, laughing in delight and trying to mount Kuroo’s chin.

Kuroo can feel Bokuto’s wet cock slide around his jaw, but he can’t bring himself to care. Everything about Bokuto right is so small and so _soft_ and it’s only getting him harder. He starts to hump the mattress while licking long stripes up Bokuto’s body, and places a firm kiss, which makes Bokuto squeal, right on his forehead. “You taste so good.”

“You _feel_ so good, Tetsu,” Bokuto sighs, still trying to mount Kuroo’s face. “Just-- Lemme-- I want to try something.”

Kuroo remains still so Bokuto can arrange himself in place. He crawls horizontally along the seam of Kuroo’s lip. It’s a bit awkward and Kuroo huffs what would be a question, but Bokuto shushes him.

“Just don’t bite me, okay?” Without giving him a chance to respond, Bokuto shoves a leg in Kuroo’s mouth until his ass and balls slot against the corner where Kuroo’s top and bottom lips meet. Bokuto lets out a hum as he begins to rub his body against Kuroo’s fat bottom lip, admitting, “your breath stinks but I’m too turned on to care.”

Kuroo breathes with his mouth on Bokuto just for that, but Bokuto merely laughs back a sarcastic, “sexy.”

It’s weird and strange and unlike anything Kuroo ever thought would get him off, but Bokuto wiggling in his mouth, his limbs clamping his bottom lip and sometimes pushing against his teeth or gums, has him oddly aroused. He adds his tongue without prompting, slowly sliding it along the length of Bokuto’s body, drawing out a deep, low moan that’s swallowed by Kuroo’s.

“ _Yessss,_ ” Bokuto exhales in a voice that’s too high for him, but Kuroo finds that he likes it. Kuroo knows it will take trust from Bokuto, but he covers his teeth with his lips likes he does for blowjobs and closes his mouth over Bokuto, though not clamping down. With his lips sealed for suction, he alternates between humming and sucking -- gently -- and earns a series of sharp cries and thrusts until Bokuto comes with a scream.

Kuroo releases Bokuto from his mouth, trying not to pay any mind to how one of their pillows is now covered in Kuroo’s spit and Bokuto’s body fluids, and sits up. Bokuto looks small, but his body is still thick, firm, and strong, and he has to massage his jaw for a little bit, feeling a bit sore now. He tastes Bokuto, but only for a second, and just as quickly, the taste is gone.

Once he feels confident, Kuroo teases, “somebody enjoyed themselves,” and finds that his voice feels raspy, though in a different way than when he sucks off Bokuto.

“That was _so_ good,” Bokuto slurs lazily, riding out his orgasm. “Ten out of ten, would do again.”

“Seven,” Kuroo confesses, now reminded of his own desire after getting Bokuto off. He grabs the lotion from his backpack as Bokuto explains the wonders of his newfound vore fetish, squeezing just enough to cover his palm. Kuroo slides his slick hand to his heavy cock, breathing softly.

“Next time we’ll do it the other way around and I’ll lick your ass so hard.” Kuroo just sighs agreeably. Bokuto’s eyes snap open and he sits up, gasping at the sight of Kuroo jerking himself off. “No! I wanted to do that!”

“You’re too small,” Kuroo points out, laying on his side so that he’s facing the pillow Bokuto’s defiled. “Your hands wouldn’t do anything. But it’s fine like this as long as you’re here.”

“I’m gonna do it!” Bokuto says insistently, hopping off the pillow and launching himself at Kuroo’s dick. Kuroo hisses at the contact but soon hisses for an entirely different reason when Bokuto clasps his arms and legs around the head of his cock and slides down the length.

“Holy fuck do that again,” Kuroo begs, hips bucking, once Bokuto’s rubbing against his pubic hair and balls. Bokuto slaps Kuroo’s balls experimentally and the gentle slaps of his smaller form feel amazing against his sensitive skin, but it’s not quite like the slide he just experienced. He cups Bokuto in a palm and slides him up his cock again, and this time when Bokuto slides down, he flexes his biceps and quads. “ _Shit._ ”

“Told you so,” Bokuto mocks, somehow managing to climb Kuroo’s dick and do it again, this time licking down a single vein as he rides Kuroo’s cock. “Lay on your back, Tetsu.”

Kuroo does as he’s told and Bokuto laughs with the shift, now standing up carefully so as to not hurt Kuroo. Standing up, he’s exactly the size of Kuroo’s cock, and Bokuto’s first order of business is to press against it, sliding from front to back, back to front, and side to side as he hugs Kuroo’s dick against his body. Bokuto’s an attentive and eager lover, traits which have always made him a good lay, especially because he was willing to try things others wouldn’t dare. Right now, his traits are paying off. Kuroo’s not sure how to describe what Bokuto is doing with his body against penis, but it feels _good_.

Bokuto only laughs when Kuroo starts to thrust into the air, feeling a new kind of pleasure and denial with Bokuto’s body wrapped around his cock but nothing to thrust into. Kuroo’s drowning in it and it’s quickly starting to feel like too much. “Hurry up, Kou. I’m close.”

“I can feel everything moving, Tetsu,” Bokuto coos, increasing his pace. “It’s so sexy. You’re so sexy. I can’t wait to see you come like this.”

Kuroo whines and notices his heels digging into the mattress and his knees bending. The upper half of his body is tensing and releasing in place, and his hands are digging into the mattress. He starts to feel his impending orgasm as Bokuto rocks and slides against his cock, playing with the sensitive, leaking head, and smearing his precome in all the right places. His breathing increases and he feels his head tilt back, releasing Koutarou’s name in a low, soft, full-bodied moan when his orgasm takes him.

Kuroo tries to focus on the way Bokuto’s laughing and probably playing with his come as he releases, but his eyes and body feel heavy now. He doesn’t have Bokuto’s energy to ride a cock immediately after coming, and the soreness of staying in one position from driving all day is catching up with him. Kuroo simply allows Bokuto to pet his softening cock and balls as much as he likes, wanting to give into the sleep calling his name.

“That was fun,” Bokuto says nearby. “We should do it again sometime.”

Kuroo cracks a single eye to see Bokuto looming over his face from the pillow, drenched in his come from his hair all the way down to feet, but all Kuroo can manage is a soft laugh. “Sure.”

Kuroo’s eye shuts and he’s not sure what Bokuto’s doing again, other than he’s rolling around and making the pillow shake. “I’m gonna clean myself with this pillow case, so we should wash it tomorrow. Do you want me to clean you off too?”

“Nah, I got it,” Kuroo answers, and takes a page out of Bokuto’s book, yanking on a spare pillow until the pillowcase unsheathes and uses that to wipe his dick and the little come that remains on his chest or thighs. “You were thorough.”

“I love playing with your come,” Bokuto says, and Kuroo feels him snuggle against his neck. “Now turn around and use the last two pillows we have for your stupid hair. If you roll around in your sleep, you’re going to crush me.”

Kuroo groans but obeys, knowing Bokuto is right. He rolls onto his stomach and presses the two pillows against his ears like he always does, and finally, _finally_ waits for sleep to take him.

Bokuto crawls between the pillows and curls up in the crook of Kuroo’s jaw and his shoulder. He stamps a few kisses along Kuroo’s neck and asks, “ten out of ten?”

“Ten out of ten,” Kuroo agrees, reaching a hand up to cup Bokuto in his sleep.

-

In the morning, Kuroo wakes up to Bokuto spooning him and a relieved sigh of, “thank _god_ it’s regular sized again.” Kuroo smiles and presses against his lover, happy to feel the proof of Bokuto’s returned size between his bare ass cheeks. Bokuto’s thick, heavy hand roams over Kuroo’s hip and up the long expanse of muscles and bones he couldn’t reach or touch in his smaller state.

“So,” Bokuto begins, licking the cove of Kuroo’s ear, “what other serums did you bring?”

 

**Author's Note:**

> “Dude!” Bokuto -- full-sized Bokuto -- yelps, immediately pressing his hands and face against a shop’s display window. “We have to get that!”
> 
> “What is it?” Kuroo asks, looking over to see Bokuto point to the Moschino exclusive Ken doll's clothes. “Oh yeah, you’d look super sexy in that. We have to buy it.”


End file.
